A cultural shaming campaign would have been meaningless without the crippling legislations that followed through the tobacco campaign.
Either way, what you're missing is that obesity is fundamentally a health problem-- and not an image problem. Therein lies the difference. From a quick visual perspective, it is impossible to discern between someone who might have a decent amount of surface fat (but otherwise be completely healthy) to someone who is definitely obese. So, public shaming of obesity would moreso be an attack on all people who didn't satisfy the visual, arbitrary imagination of what our society deems as 'a healthy weight'.
Not only that, but an emphasis on tackling the issue of obesity through government & legislative change also has the propensity to tackle other chronic health issues that people suffer from even though they might not be obese! Plenty of non-obese individuals suffer from cancer, heart disease, and diabetes. How will shaming address these sicknesses?
I'm not saying this is a complete solution. I understand obesity's correlation with poverty (in developed countries), education, and historical circumstance (ex Tonga). But in some cases, like that of Kelly Clarkson, the situation can improve with increased social pressure.
